Abstract: To provide a single universal charging apparatus, capable of charging at high speed and efficiency any type of secondary battery, and capable of charging secondary batteries any arbitrary charging rate.In selecting the arbitrary amount of current from low current to high current while charging a variety of secondary batteries, the voltage and temperature of the battery are monitored, so that either at the point at which the rate of rise of the temperature of the battery exhibits an increase over the immediately previous rate of rise that exceeds a given reference value, or at the point at which the difference in change of battery voltage is decreased continuously for a preestablished amount of time, the charging of the battery is stopped.

Abstract: A method and apparatus for charging nickel-cadmium batteries with a current greater than 2C rate. The cell temperature or both the temperature and voltage thereof are monitored, and the charging operation is halted upon detection of a moment when the rate of temperature increase of the cell became at least twice as great as the rate of temperature increase that was measured just before, or of a moment at which the above phenomenon took place and a moment at which the rate of voltage increase has declined immediately following a period during which the rate of voltage increase has continually risen.

Abstract: A device for and a method of indicating the residual capacity of a secondary cell, that needs be recharged using a simply constituted device, correctly and within a short period of time.